1. Field of the Invention
The present invention relates to improved methods for detecting and treating tumors and lesions and obtaining biopsy material in the course of intraoperative, laparoscopic, intravascular, and endoscopic examination using a small detection instrument or monitor. In preferred embodiments, the methods utilize a labeled divalent single chain antibody fragment or subfragment with a molecular weight of 85,000 daltons or less that specifically binds to an antigen produced by or associated with the tumors or lesions. Alternatively, bispecific F(ab).sub.2 and F(ab').sub.2 fragments can also be used for pre-targeting according to the present invention, if non-targeted fragments are cleared, and a bivalent diagnostic hapten is then administered to facilitate target detection and possibly other procedures within 48 hours of the first injection.
2. Description of the Prior Art
Surgical resection remains the primary curative approach in the management of cancer. Radioimmunodetection (RAID) is used to locate and stage tumors, and to monitor post-operative patients, by external imaging, after injection of a radiolabeled antibody. Antibodies and/or antibody fragments which specifically bind antigens produced by or associated with tumors ("anti-cancer antibodies") are used as carriers for radiolabels in RAID. It will be appreciated, that a tumor antigen can serve as a target for an antibody carrier even if it is not present in serum in a detectable amount.
Resolution is affected by several factors that can limit the size of a tumor, especially a metastasis, which can be imaged by RAID. Non-invasive RAID is inherently limited by the distance between the radiation detector and the tumor. In the case of small, deep-seated metastatic tumors, this becomes the limiting factor in their detection.
Second-look surgery has been practiced where recurrence of a previously excised primary tumor was indicated by elevated levels of tumor marker, e.g., carcinoembryonic antigen (CEA). Recently, a small gamma detection probe has been developed which is capable of detecting gamma emission at short distances. Its intraoperative use in second-look surgery has been reported to provide important information to the surgeon for determining safe margins for resection and for detecting small metastases, by Aitken et al., Dis. Colon Rectum, 27, 279-282 (1984).
Nevertheless, elevated background radiation levels can interfere with and vitiate the advantage of short measuring distances in this technique. In addition, non-specific immunoglobulin uptake by tumor tissue can complicate diagnosis.
U.S. Pat. No. 4,782,840 discloses a method for reducing the effect of elevated background radiation levels during surgery. The method is to inject the patient with antibodies specific for neoplastic tissue and which are labeled with radioisotopes having a suitably long half-life, such as Iodine-125. After injection of the radiolabled antibody, the surgery is delayed at least 7-10 days, preferably 14-21 days, to allow any unbound radiolabeled antibody to be cleared to a low bloodpool, background level.
U.S. Pat. No. 4,932,412 discloses methods for reducing or correcting for non-specific background radiation during intraoperative detection. The methods include the administration to a patient who has received a radiolabeled primary antibody, of a contrast agent, subtraction agent or second antibody which binds the primary antibody.
Tumors can be detected in body cavities by means of directly or indirectly viewing various structures to which light is delivered and then collected. Lesions at any body site can be viewed so long as nonionizing radiation can be delivered and recaptured from these structures.
The prior art discloses improvements of such imaging approaches by using certain dyes that are accreted by lesions, such as tumors, which are in turn activated by a specific frequency of light. These improvements are described in Dougherty et al., Cancer Res. 38:2628, 1978; Dougherty, T. J., Photochem. Photobiol. 45:879, 1987; Jori and Perria, eds., Photodynamic Therapy of Tumors and Other Diseases; Padua: Libreria Progetto, 1985; Profio, Proc. Soc. Photoopt. Instr. Eng. 907:150, 1988; Doiron and Gomer, eds., Porphyrin Localization and Treatment of Tumors; New York: Alan Liss, 1984; Hayata and Dougherty, Lasers and Hematoporphyrin Derivative in Cancer; Tokyo: Igaku-Shoin, 1984; and van den Bergh, Chem. Britain 22:430, 1986, incorporated herein in their entirety by reference.
These dyes are injected, for example, systemically, and laser-induced fluorescence can be used by endoscopes to detect sites of cancer which have accreted the light-activated dye. For example, this has been applied to fluorescence bronchoscopic disclosure of early lung tumors (Doiron et al., Chest 76:32, 1979, included herein by reference; and references cited above).
It is known that dyes can be attached to antibodies for a more specific binding to certain tissues and cells, including malignant and normal cells, depending upon the discriminatory power of the antibodies in question. In cancer, such labeled antibodies have been used in flow cytometry and in immunohistology to stain malignant cells with many different kinds of anticancer antibodies, as described, for example, in Goding, Monoclonal Antibodies: Principles and Practice; London/New York, Academic Press, 1983; Ferrone and Dierich, eds., Handbook of Monoclonal Antibodies; Park Ridge, N.J., Noyes Publications, 1985; Wick and Siegal, eds., Monoclonal Antibodies in Diagnostic Immunohistochemistry; New York/Basel, Marcel Dekker, 1988, incorporated herein in their entirety by reference. Fluorescent and other chromagens, or dyes, such as porphyrins sensitive to visible light, have been used to detect and even treat lesions by directing the suitable light to the tumor or lesion (cited above). In therapy, this has been termed "photoradiation, phototherapy, or photodynamic therapy (Jori and Perria, eds., Photodynamic Therapy of Tumors and Other Diseases, Padua: Libreria Progetto, 1985; van den Bergh, Chem. Britain 22:430, 1986).
Monoclonal antibodies have been coupled with photoactivated dyes for achieving a photodetection or photocopy (Mew et al., J. Immunol. 130:1473, 1983; idem., Cancer Res. 45:4380, 1985; Oseroff et al., Proc. Natl. Acad. Sci. USA 83:8744, 1986; idem., Photochem. Photobiol. 46:83, 1987; Hasan et al., Prog. Clin. Biol. Res. 288:471, 1989; Tatsuta et al., Lasers Surg. Med. 9:422, 1989; Pelegrin et al., Cancer 67:2529, 1991--all incorporated in their entirety herein by reference). However, these earlier studies did not include use of endoscopic imaging and/or therapy or biopsy applications, especially with the use of antibody fragments or subfragments.
Further, there is a need in the art to utilize antibodies and antibody fragments that provide superior targeting specificity and affinity but which are cleared quickly and naturally through the kidneys or which can be cleared quickly with clearing agents, so that targeting can be effected within 48 hours
A need continues to exist for simple methods which permit enhanced resolution to be achieved for close range intraoperative, intravascular, and endoscopic lesion detection, biopsy and therapy.
A need also exists for improved methods for detection and therapy of tumors.
A need also exists for methods to enable a clinician to intraoperatively, laparoscopically, intravascularly or endoscopically detect and treat non-malignant pathological lesions.
A need further exists for methods to accurately locate lesions in a patient to guide the biopsy implement to the lesion during a biopsy procedure.